The "find $stuff -print0 | xargs -0 $command" pattern causes both find and xargs to use null-delineated paths, greatly reducing the probability of either hiccuping on even the weirdest of file/path names.

It's also not strictly necessary to add the {} at the end of the xargs command line, as it'll put the files there automatically.

Mind, in most environments, you could use find's "-exec" option to bypass xargs entirely:

will use xargs-like "make sure the command line isn't too long" logic to run the mogrify command as few times as necessary (to run once per file, use a ';' instead of a '+' - just be sure to escape it properly).